Diagnosis of Misery Perfusion Using Noninvasive
15O-Gas PET
Masato Kobayashi1,2, Hidehiko Okazawa1, Tatsuro Tsuchida3, Keiichi Kawai1,2, Yasuhisa Fujibayashi1, andYoshiharu Yonekura1
1Biomedical Imaging Research Center, University of Fukui, Fukui, Japan; 2Graduate School of Medical Science, Kanazawa University,
Kanazawa, Japan; and 3Department of Radiology, Faculty of Medical Sciences, University of Fukui, Fukui, JapanTo avoid arterial blood sampling and complicated analyses in
15O-gas PET studies, we evaluated a noninvasive techniqueusing the count-based method for measuring asymmetric increases in oxygen extraction fraction (OEF) in cerebrovasculardisease. Methods: Eighteen patients (mean age 6 SD, 61 6
16 y) with atherothrombotic large-cerebral-artery disease werestudied for the measurement of hemodynamic parameters using
the 15O-gas steady-state method with inhalation of 15O2, C15O2,
and C15O. All patients also underwent H215O PET with the bolus
injection method. Count-based ratio images of 15O2/C15O2 and15O /H 15O were calculated, and asymmetry indices (AIs) were2
2
obtained (cbOEFSS-AI and cbOEFBO-AI, respectively) using regions of interest drawn bilaterally on the cerebral cortices. These
AIs were compared with the AIs of absolute OEF (qOEF-AI) andwith those after cerebral blood volume (CBV) correction. A contribution factor for this correction was defined as a variablea, and the effect of the correction was evaluated. Results:
cbOEFSS-AI underestimated qOEF-AI significantly, especiallywith a greater AI (P , 0.05). cbOEFBO-AI linearly correlated
well with qOEF-AI. CBV correction improved the slopes of regression lines between qOEF-AI and cbOEFSS-AI, and the optimal a was defined as 0.5. On the other hand, cbOEFBO-AI fairly
estimated qOEF-AI without CBV correction. Correlation between
qOEF-AI and cbOEFBO-AI was adversely affected, and the mean
bias was increased, with a greater a. Conclusion: cbOEFBO-AI
can fairly estimate the AI of OEF without CBV correction,
whereas cbOEFSS-AI might require CBV correction for better estimation. The examination time and stress to patients would be
reduced with the count-based method because it is noninvasive.
Key Words: oxygen extraction fraction; misery perfusion; gas
PET study; noninvasive method; cerebrovascular disease
J Nucl Med 2006; 47:1581–1586

M

easurement of the cerebral oxygen extraction fraction (OEF) with PET provides information on the hemodynamic status of patients with cerebrovascular disease.
Misery perfusion, defined as an increase in OEF in the
Received Mar. 2, 2006; revision accepted Jun. 26, 2006.
For correspondence or reprints contact: Hidehiko Okazawa, MD, PhD,
Biomedical Imaging Research Center, University of Fukui, 23-3 MatsuokaShimoaizuki, Eiheiji-cho, Fukui 910-1193, Japan.
E-mail: okazawa@fmsrsa.fukui-med.ac.jp
COPYRIGHT ª 2006 by the Society of Nuclear Medicine, Inc.

ischemic brain region (1–7), is caused by a decrease in cerebral blood flow, presumably due to a reduction in cerebral
perfusion pressure and disturbance of cerebral autoregulation. Because patients with misery perfusion in stage II
ischemia are considered to have a significantly higher strokerecurrence ratio than are patients without misery perfusion(2,5,6), it is important to evaluate the hemodynamic statusof those patients with atherothrombotic large-cerebral-artery
occlusive disease whether neurosurgical treatment is needed
or not.
Several methods for measurement of quantitative OEF(qOEF) with PET have been developed and used (3,4,8–12).
The steady-state method with inhalation of 15O-gas is widelyused in Japan as a simple and practical method for measurement of cerebral blood flow, OEF, and the cerebral metabolic
rate of oxygen (CMRO2) (3,8). Mintun et al. developed the
3-step method with bolus injection of 15O-water and bolus
inhalation of 15O2 to measure cerebral hemodynamic parameters (4). These methods for qOEF measurement are used
for evaluation of hemodynamic impairment; however, theyrequire arterial blood sampling during the PET examination.
Establishing an arterial line before PET studies is invasive andtime consuming and exposes the patient to unnecessary risks(13). For this reason, the simple method of count-based measurement of OEF has been proposed and is expected to be a
substitute method for detection of misery perfusion (14–16).
The purpose of this study was to evaluate whether thecount-based OEF (cbOEF) method can detect misery perfusion correctly in the affected cerebral regions of patientswith chronic cerebrovascular disease. The cbOEF method
can noninvasively evaluate asymmetric increases of OEF
with a simple calculation (14–16). However, the method forthis semiquantitative assessment has not been sufficiently
established as to which method for tracer administration andimage calculation is appropriate for evaluation of side-to-side
OEF differences to detect misery perfusion. In the present
study, cbOEFs obtained from 2 methods—continuous 15O-gas
inhalation and bolus H215O injection—were applied to calculate left-to-right ratios of OEF in patients with symptomatic
severe stenoocclusive disease in the major cerebral arteries.
The effect of cerebral blood volume (CBV) correction on
cbOEF was also evaluated in both methods.

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MATERIALS AND METHODS
Subjects
The study consisted of 18 patients (16 men and 2 women; meanage 6 SD, 61 6 16 y) with ischemic cerebrovascular disease.
Seventeen had occlusion (n 5 8) or stenosis (n 5 9, .70%
diameter reduction) in the right or left internal carotid artery (n 516) or in the middle cerebral artery (n 5 1). The remaining patient
had stenotic lesions in the right internal carotid artery and left
middle cerebral artery. Six had experienced transient ischemic
attacks, 10 had had a nondisabling hemispheric stroke with minor
cerebral infarction shown on MRI, and 2 had no neurologic symptoms. The mean interval between the latest ischemic event and theindividual PET scan was 3.4 6 3.7 mo. The patients underwent
MRI, MR angiography, or conventional angiography to examine
all cerebral and arterial lesions. The percentage reduction in the
diameter of stenotic lesions was measured by conventional angiography or ultrasonography for cervical lesions and by conventional angiography for intracranial lesions. The study wasapproved by the Ethical Committee of the University of Fukui,
Faculty of Medical Sciences. Written informed consent was obtained from each subject before the study.
PET Procedures
All patients underwent PET with a whole-body tomographyscanner (Advance; GE Healthcare), which permits simultaneous
acquisition of 35 image slices with an interslice spacing of
4.25 mm (17). Performance tests showed the intrinsic resolutionof the scanner to be 4.6–5.7 mm in the transaxial direction and
4.0–5.3 mm in the axial direction. Transmission scanning was
performed for 10 min using the 68Ge/68Ga line source for attenuation correction in each subject before tracer administration. Allemission scans were acquired in 2-dimensional mode. The PET
data were reconstructed using a Hanning filter with a resolution of
6.0 mm in full width at half maximum in the transaxial direction.
Patients were positioned on the scanner bed with their heads
immobilized using a head holder. A small cannula was placed in
the right brachial artery for blood sampling. In the steady-statemethod, 15O2 (740 MBq/min) and C15O2 (370 MBq/min) wereinhaled continuously for approximately 8 min, and static PET
scanning was then started and continued for 5 min to calculate
images of cerebral blood flow, OEF, and CMRO2 (3,8,18). Eachsubject also inhaled C15O as a single dose of 1,000 MBq for CBVmeasurement (18). PET scanning was started at least 30 s after the
tracer count had peaked in the brain and was continued for 3 min.
Arterial blood was sampled 2 or 3 times during each procedure of
the 15O-gas study to measure quantitative hemodynamic parameters. The radioactivity in the blood samples thus obtained was
immediately measured with a scintillation counter to determine
arterial blood activity. During continuous inhalation of 15O2 in thesteady-state method, the sampled blood was divided into 2 aliquots
to count the radioactivity of whole blood and plasma. Before
the 15O-gas scans, all patients also underwent H215O PET with a3-min acquisition started at the time of bolus injection of the tracer(740 MBq). These data were used for calculation of the cbOEF
image (14,16). To reduce the influence of intravascular radioactivity, we eliminated the initial frames (about 30 s) of dynamic
PET data in the H215O bolus scan before count summation (19).
Absolute values of cerebral blood flow, CBV, OEF, and CMRO2
were obtained from image calculation of the steady-state method(3,8). A cerebral-vessel–to–large-vessel hematocrit ratio of 0.85

1582

was used in the calculation of CBV (20,21). The individual CBV
image thus obtained was used for correction of the qOEF image toreduce the effect of radioactivity in the cerebral vessels (8). Total
arterial O2 content measured from the arterial blood sampled ineach 15O2 scan was used in the calculation of the CMRO2 image.
Data Analysis
Regional values were obtained from regions of interest (ROIs)
drawn bilaterally on 3 slices of the cerebral cortex. Elliptic ROIs
at 15 · 50 mm were placed bilaterally on cortical territories of the
middle cerebral artery at the level of the centrum semiovale (Fig.
1). Before ROIs were placed, images of hemodynamic parameters
and individual MR images were normalized anatomically for eachsubject using SPM2 (Wellcome Department of Cognitive Neurology). The ROIs placed in the ipsilateral hemisphere using normalized MR images were copied symmetrically at correspondent
regions of the contralateral hemisphere in the standard brain
space. In patients with cerebral infarction, the ROIs were placedso as to avoid the area of infarction on the normalized individual
MR images. The same ROIs were applied to all parametric imagesof each subject. The values obtained from the ROIs were averaged
for each hemisphere.
The cbOEF images were obtained from simple pixel-by-pixel
calculation of count ratios by 15O2/C15O2 (cbOEFSS) and 15O2/
H215O (cbOEFBO). The asymmetry index (AI 5 [ipsilateral]/[contralateral]) of regional OEF was obtained from the cbOEF
image (cbOEFSS-AI and cbOEFBO-AI). The values of cbOEF-AI
were compared with that of absolute OEF (qOEF-AI). BecauseqOEF was corrected for the influence of blood volume using the
CBV image, blood volume correction was considered necessary
for cbOEF to correlate better with qOEF. To remove the influenceof blood volume on regional values, we corrected the cbOEF using
counts of the C15O image (Bq/g) with the following equations,which were modified and simplified from the method of CBVcorrection for absolute OEF of Lammertsma et al. (8):cbOEFC 5

cbOEF 2 a  XCO
1 2 a  Xco
CCO2 =SCO
CH2 O =SCO
XCO 5
;
or
CCO2 =CCO
CH2 O =CCO

Eq. 1

Eq. 2

where cbOEFC is the corrected cbOEF, a is a contribution factor
for the blood volume correction in the count-based method, SCO(Bq/g) is the regional value in the sagittal sinus obtained from

FIGURE 1. qOEF and cbOEF images obtained from a single
patient. ROIs placed bilaterally on middle cerebral artery
territories are shown in qOEF image. cbOEFSS was calculated
from division of 15O2 and C15O2 images in steady-state method,and cbOEFBO was calculated from 15O2 and bolus H215O PET.
cbOEF images are not corrected for effect of intravascularradioactivity using C15O image. Note high values in sagittal sinus.

THE JOURNAL OF NUCLEAR MEDICINE • Vol. 47 • No. 10 • October 2006

TABLE 1
Hemispheric Differences in Cerebrovascular Diseases (n 5 18)
Parameter

Ipsilateral

ContralateralAIP*

CBF (mL/min/100 g)
CMRO2 (mL/min/100 g)
OEF (%)CBV (mL/100 g)

32.7 6 7.5
2.68 6 0.42
48.6 6 11.7
4.59 6 0.79

39.2 6 5.9
3.02 6 0.39
44.5 6 6.1
4.26 6 0.74

0.84 6 0.15
0.89 6 0.11
1.08 6 0.14
1.09 6 0.12

,0.01
,0.01
,0.05
,0.05

*By paired t test.
CBF 5 cerebral blood flow.

ROIs on the C15O image, and CCO2, CH2O, and CCO are regionalcounts in the C15O2, H215O, and C15O images, respectively. To
determine SCO, we drew 3 small, circular ROIs (5 mm in diameter)on the sagittal sinus using the C15O image, and the mean of the ROI
counts was assumed to be 1 (mL/g) because the sinus should include
only blood (21). The effect of a on cbOEFC was evaluated with anassumption that an optimal value of a should exist for correction ofblood volume because XCO should be affected by a partial-volume
effect of the sagittal sinus and image resolution. Correlation coefficients between qOEF-AI and cbOEFC-AI, and the mean distanceof all plots from the line of identity (bias), were calculated as afunction of a.
Differences between qOEF-AI and cbOEFSS-AI or cbOEFBOAI were compared statistically using repeated-measures ANOVA
and a paired t test. The effect of the blood volume correction on
cbOEF-AI was also evaluated using a paired t test. P values of lessthan 0.05 were considered to indicate a significant difference.
RESULTS

Hemodynamic parameters calculated from all patientsare given in Table 1. In 1 patient who had lesions of mild
stenosis in the right internal carotid artery and severe
stenosis in the left middle cerebral artery, the side of themore severe stenotic lesion was defined as ipsilateral. All
parameters were significantly affected by the stenoocclusive lesion in the ipsilateral hemisphere. Figure 1 shows
representative images of qOEF, cbOEFSS, and cbOEFBO
calculated from a single patient’s data. cbOEF images arepresented without CBV correction. qOEF and cbOEF
images were similar, although cbOEF showed higher values
in the sagittal sinus than did qOEF. Because the qOEF
images were calculated from 15O2 and C15O2 data in thesteady-state method, the cbOEFSS and qOEF images weresimilar, whereas values in the sagittal sinus were higher for
cbOEFSS images than for cbOEFBO images.
The relationship between qOEF-AI and cbOEF-AI without CBV correction is presented in Figure 2. Both cbOEFAIs (cbOEFSS-AI and cbOEFBO-AI) linearly correlated well(r 5 0.98 and 0.92, respectively) with qOEF-AI. However,cbOEFSS-AI significantly underestimated the AI of OEF(P , 0.05; paired t test), especially with a greater AI (y 50.64x 1 0.36) (Fig. 2A). The difference between cbOEFBO-AI
and qOEF-AI was not significant (y 5 1.00x 1 0.02) (Fig. 2B).
To remove the effect of radioactivity on the vascularblood volume, we calculated cbOEFC using the C15O
image. Table 2 shows the slope, square of the correlation
coefficient, bias, and coefficient of variation obtained fromthe relationship between qOEF-AI and cbOEF-AI simulated by changing the contribution factor of a. The slope
between qOEF-AI and cbOEFSS-AI was improved by the
CBV correction with an increase of a; however, thatbetween qOEF-AI and cbOEFBO-AI was farther from theline of identity with a greater a. The graphs in Figure 3
show the correlation coefficient and bias between qOEF-AI
and cbOEF-AI as a function of a. The square of thecorrelation coefficient between qOEF-AI and cbOEFSS-AI
was maximal when a was close to 0.5 (Fig. 3A), although
the mean bias continued to decrease up to an a of 0.7 (Fig.
3B) and increased with a greater a. The square of thecorrelation coefficient between qOEF-AI and cbOEFBO-AI
was maximal at an a of 0 (without CBV correction) and decreased with a greater a. The bias was gradually increased
when a was greater than 0.5.

FIGURE 2. Correlation of qOEF-AI andcbOEFSS-AI (A) or cbOEFBO-AI (B) in all
patients (n 5 18). Both cbOEF-AIs arelinearly well correlated. However, cbOEFAISS underestimated qOEF-AI significantly, especially with a greater AI (P ,0.05), whereas cbOEF-AIBO was not significantly different from qOEF-AI. Dashedline is line of identity.

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TABLE 2
Correlations Between qOEF-AI and cbOEF-AI
qOEF-AI vs. cbOEFSS-AI
a Slope*r2

Bias (%)y

0
0.3
0.5
0.7
1.0
1.2
1.4
1.6

0.96
0.98
0.98
0.98
0.96
0.91
0.84
0.75

2.8
2.4
2.2
2.1
2.3
2.6
3.0
3.5

0.64
0.68
0.71
0.73
0.78
0.82
0.86
0.91

qOEF-AI vs. cbOEFBO-AI

CV Slope*

r2

1.1
1.2
1.2
1.1
0.9
0.8
0.9
1.2

0.84
0.84
0.83
0.82
0.77
0.71
0.62
0.45

1.00
1.05
1.09
1.13
1.19
1.24
1.29
1.31

Bias (%)y CV
3.5
3.8
4.0
4.4
5.1
6.2
7.8
10.7

0.8
0.9
0.9
0.9
1.0
1.0
1.0
1.1

*Slope of regression line between qOEF-AI and cbOEF-AI.
yMean bias in plots between qOEF-AI and cbOEF-AI.
CV 5 coefficient of variation.

DISCUSSION

Evaluation of hemodynamic status is important in chronic
atherothrombotic internal-carotid-artery or middle-cerebralartery occlusive disease because patients with misery perfusion have a higher risk of stroke recurrence than dopatients with a normal OEF (2,5,6). 15O-gas PET is a useful
method for evaluation of hemodynamic parameters andassessment of OEF to detect misery perfusion. The original
method for evaluation of cerebral oxygen consumption was
proposed by Jones et al. using the noninvasive steady-statemethod (22), and the concept of misery perfusion wasreported by Baron et al. using the similar count-based
method (1). This noninvasive method was modified, andquantitative measurements were established for evaluationof hemodynamic parameters (3,4,8). However, these quantitative methods require arterial blood sampling, which
prevents their use in clinical studies because of the lengthy
time required to evaluate 1 patient, including the time toestablish the arterial line and to make other arrangements
for the study. The noninvasive count-based method in the
15O-gas PET study is useful, lacks these problems, and canbe made widely available in PET centers with an in-house
cyclotron. An advantage of this count-based method would
be the possibility of conducting patient studies efficiently,
quickly, and successfully without complicated procedures

to yield quantitative metabolic data (4,23). However, thisrelative method has not been validated as to whether the AI
of OEF can appropriately detect misery perfusion without
CBV correction (14,16).
In the present study, both cbOEF-AIs showed a linear
correlation against qOEF-AI, although cbOEFSS-AI significantly underestimated qOEF-AI. The correlation coefficient was better in cbOEFSS-AI than in cbOEFBO-AI. To
improve the slope of the correlation, we corrected the blood
volume for cbOEF because qOEF was corrected for theeffect of CBV. As observed in regional differences in hemodynamic parameters, CBV was significantly greater in theipsilateral hemisphere than in the contralateral hemisphere,
and this difference was considered to affect cbOEF values.
In cbOEFSS-AI, the CBV correction using Equation 1 improved the slope of the correlation, and the correlation coefficient was better at an a of 0.5 than with no CBV correction.
On the other hand, cbOEFBO-AI showed no improvement
in slope or mean bias with CBV correction. Derdeyn et al.
assumed that the cbOEF image without CBV correction
would enhance OEF-AI with a higher vascular radioactivity
due to vasodilatation caused by a decrease in perfusionpressure in the compromised region (14). However, unexpectedly, cbOEFSS-AI showed an underestimation of qOEF-AI,
and the slope of the correlation was improved by CBVcorrection with an appropriate contribution factor of a, although an a greater than 0.8 decreased the correlation coefficient and increased bias. This underestimation might be causedby the greater influence of blood volume, or intravascular radioactivity, on the CO2 image than on the O2 image, although
we did not evaluate which image was more influenced bychanges in CBV in the present study. Thus, in the steady-statemethod, CBV correction with an appropriate a (about 0.5
in our method), combined with correction by the slope ofcorrelation, would provide better results than would uncorrected cbOEFSS-AI. On the other hand, cbOEFBO-AI showeda fair correlation with qOEF-AI, and the correlation coefficient was maximal at an a of 0. This result means that cbOEFAI can be used without CBV correction in the bolus method.
In the image of cbOEFBO, the early arterial phase of dynamic
data was eliminated to reduce the influence of vascularradioactivity (19), which may have reduced the effects ofblood volume on the cbOEFBO image.

FIGURE 3. Changes in r2 (A) and bias (B)calculated from plots of qOEF-AI vs.
cbOEF-AI obtained by CBV correction withchanges in contribution factor of a. Bias ismean of absolute distance between eachplot and line of identity. Correlation coefficient between qOEF-AI and cbOEFSS-AI(solid line) was maximal when a was close
to 0.5, and mean bias was minimal when awas 0.7. In contrast, correlation coefficient
in relationship between qOEF-AI andcbOEFBO-AI (dashed line) was maximal
and bias minimal when a was 0.

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THE JOURNAL OF NUCLEAR MEDICINE • Vol. 47 • No. 10 • October 2006

Grubb et al. (5) and Derdeyn et al. (14) tried to estimate therisk of recurrent stroke in patients with symptomatic carotid
artery occlusion using cbOEF-AI. They applied the regional
AI of OEF obtained from the 15O2/H215O ratio using thebolus method after normalization of the global cbOEF mean
to get 0.40. Sensitivity and specificity between qOEF andcbOEF were similar in the analysis of receiver operating
characteristics in the prediction of recurrent stroke (14).
Ibaraki et al. reported the count-based method using look-up
tables for relative measurement of cerebral blood flow, OEF,
and CMRO2 (16). For the calculation of the look-up tables,
cerebral blood flow and OEF in the reference brain region
were assumed to be 50.0 (mL/min/100 mL) and 0.40, respectively. The constant CBV value of 4.0 (mL/100 mL) was usedover the whole brain as well. Ibaraki et al. reported that thedifferences in CBV caused large errors in estimations of OEF
and CMRO2 in cases of severe reduction of cerebral bloodflow or OEF. This result indicates a difficulty with the method
for analysis of severely impaired regions affected by ischemic cerebrovascular disease. We did not apply the global
normalization method in calculation of cbOEF and observed
excellent correlations when comparing qOEF-AI and cbOEFAI, even without CBV correction. This simple method would
be useful for clinical 15O PET studies, especially when one isusing PET/CT machines, which lead to difficulties in arterial
sampling. Furthermore, cbOEFBO-AI may not require the
C15O scan for CBV correction if the method is used only forthe diagnosis of regional misery perfusion.
The correlation coefficient was better in cbOEFSS-AI
than in cbOEFBO-AI in the present study, because qOEF
was calculated by the steady-state method and the image
was based on the 15O2/C15O2 image. If the qOEF image had
been calculated by the bolus method, cbOEFBO-AI may
have shown a better correlation. Unlike the original method
studied by Derdeyn et al. (14), our method for cbOEFBO-AI
used images of bolus water injection and continuous 15O2
inhalation. The results might be different between the 2
methods. However, the correlation between qOEF-AI andcbOEFBO-AI was acceptable even with use of the continuous inhalation method for 15O2 images. Five patients inthe present study had misery perfusion as determined by anabsolute OEF value (.52.0%) using data from healthy
volunteers in our institute. Misery perfusion in all 5 of thesepatients can be determined by a threshold of 1.17 in qOEFAI. A threshold of 1.12 with cbOEFSS-AI is identical to thatof qOEF-AI if the CBV correction is not applied (Fig. 2A).
A threshold of 1.15 in cbOEFBO-AI results in 1 false-positive
and 1 false-negative (Fig. 2B), and thus, the diagnostic accuracy
was fair in our results. However, the sample population was
small, and more patients are needed to determine an appropriate threshold for clinical diagnosis.
A disadvantage of the count-based method would bea difficulty in the detection of global changes in OEF.
Bilateral arterial lesions with severe stenoocclusive changes
may not be evaluated appropriately. However, in our experience, most patients with bilateral stenotic lesions have faircerebral circulation on the side with less severe stenosis.
Quantitative measurement of cerebral blood flow would beneeded in cases of global hemodynamic impairment.
CONCLUSION

The feasibility of the cbOEF method for detection ofmisery perfusion was evaluated with estimation of the CBV
effect on OEF-AI calculation. Our method without global
normalization for cbOEF successfully estimated OEF-AI inpatients with misery perfusion. cbOEFSS-AI obtained fromthe steady-state method would require CBV correction or
correction for the underestimation of OEF-AI, whereas
cbOEFBO-AI would not need any correction. The cbOEF
method would be useful in clinical studies for the evaluation of misery perfusion in ischemic cerebrovascular disease because it would reduce examination time and stress topatients.
ACKNOWLEDGMENTS

The authors thank Shingo Kasamatsu, Katsuya Sugimoto,Tetsuya Mori, and the rest of the staff of the Biological
Imaging Research Center, University of Fukui, for theirtechnical and clinical support. This study was partly funded
by a Grant-in-Aid for Scientific Research from the Japan
Society for the Promotion of Science (17209040), 21stCentury COE Program (Medical Science).
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Erratum
In the article ‘‘SPECT-Guided CT for Evaluating Foci of Increased Bone Metabolism Classified as Indeterminate on
SPECT in Cancer Patients,’’ by Römer et al. (J Nucl Med. 2006;47:1102–1106), Table 3 contains a transcriptional
error introduced during correction of the page proofs. The data for scapula should be 0 benign and 2 indeterminate,
instead of 1 benign and 0 indeterminate. We regret the error.

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THE JOURNAL OF NUCLEAR MEDICINE • Vol. 47 • No. 10 • October 2006